1. Field of the Invention
The present invention relates to a piston type compressor in which pistons are accommodated in cylinder bores formed in a cylinder, in which the pistons are reciprocated through rotation of a rotating shaft so that gas is sucked into and is discharged from the cylinder bores through reciprocating motion of the pistons, and in which the cylinder is incorporated in a total housing constructed by joining a first housing and a second housing together.
2. Description of the Related Art
A piston type the compressor is disclosed in, for example, Japanese Patent Unexamined Publication (Kokai) No. 10-306773 in which a cylinder is incorporated in a total housing constructed by joining a first housing and a second housing together. The construction in which the cylinder is incorporated in the total housing is a measure for keeping a joint between the first housing and the cylinder and a joint between the cylinder and the second housing unexposed to the outside of the compressor. Keeping the joints unexposed to the outside of the compressor is effective in reducing the possibility that refrigerant inside the compressor will leak therefrom.
A seal material is interposed at a joint between the first housing and the second housing. The seal material held by the first housing and the second housing therebetween prevents the leakage of refrigerant from the joint between the first housing and the second housing.
In order to produce no looseness of the cylinder in directions in which the pistons reciprocate, in the apparatus disclosed in the Japanese Patent Unexamined Publication (Kokai) No. 10-306773, a construction is adopted in which the cylinder and a valve plate are both held by the first housing and the second housing therebetween. Consequently, the first and second housings must hold the seal material and the cylinder between them. However, it is difficult to ensure that both the seal material and the cylinder are so held, due to dimensional and assembling errors of components of the compressor. If the seal material is not held in an ensured fashion, refrigerant leaks from the joint between the first housing and the second housing. If the cylinder is not held in an ensured fashion, looseness of the cylinder occurs. While looseness of the cylinder can be prevented by press fitting the cylinder in the total housing, press fitting results in deformation of the cylinder, and the deformation of the cylinder results in deformation of cylinder bores formed in the cylinder, this facilitating the leakage of refrigerant contained inside the cylinder bores past the circumferential surfaces of the pistons accommodated in the cylinder bores.
An object of the present invention is to ensure that a cylinder incorporated in a total housing constituted by a first housing and a second housing, and a seal material interposed between the first housing and the second housing are held between the first housing and the second housing.
To this end, according to an aspect of the present invention, there is provided a piston type compressor in which pistons are accommodated in cylinder bores formed in a cylinder, in which the pistons are reciprocated through rotation of a rotating shaft so that gas is sucked into and is discharged from the cylinder bores through reciprocating motion of the pistons, and in which the cylinder is incorporated in a total housing constructed by joining a first housing and a second housing together, the piston type compressor comprising a seal material provided at a joint between the first housing and the second housing so as to be held by the first housing and the second housing therebetween, and a gap absorbing body interposed between at least one of the first housing and the second housing and the cylinder, wherein in a state in which the seal material is held by the first housing and the second housing therebetween, the gap absorbing body is deformed by the first housing and the second housing so that the cylinder and the gap absorbing body are both held therebetween.
When the first housing and the second housing are caused to approach each other so as to be joined together, the gap absorbing body and the cylinder are first held by the first housing and the second housing. When the first housing and the second housing are caused to approach further so as to be joined together, the gap absorbing body is deformed to contract, and as the gap absorbing body contracts, the seal material comes to be held by the first housing and the second housing. Consequently, it is ensured that the seal material and the cylinder are held by the first housing and the second housing therebetween.
According to another aspect of the present invention, the gap absorbing body comprises an elastic body.
When the first housing and the second housing are caused to approach each other so as to be joined together, the elastic body held by the first housing and the second housing therebetween contracts while being elastically deformed.
According to a further aspect of the present invention, the gap absorbing body is formed of a soft metal, which is easy to deform.
According to a yet further aspect of the present invention, the gap absorbing body comprises a deformable projection integrally formed on at least one of the first housing and the second housing.
When the first housing and the second housing are caused to approach each other so as to be joined together, the projection contracts while being deformed.
According to a further aspect of the present invention, the gap absorbing body comprises a gap absorbing ring which conforms to the annular contour of the joint which surrounds the rotating axis of the rotating shaft.
The gap absorbing ring which conforms to the annular contour of the joint is suitable as a gap absorbing body in providing a uniform press contact between the seal material and the first housing, as well as between the seal material and the second housing.
The present invention may be more fully understood from the description of preferred embodiments of the invention set forth below, together with the accompanying drawings.